Currently, camera modules are included as a feature in a wide variety of portable electronic devices. Most portable electronic devices are becoming progressively more miniaturized over time, and camera modules are correspondingly becoming smaller and smaller. Nevertheless, consumers still demand excellent image quality.
A typical camera module includes a lens module and an image sensor. The lens module includes a lens barrel, at least one optical elements received in the lens barrel, and a lens holder. The lens barrel is partially received in the lens holder. The image sensor is received in the lens holder. In order to ensure image quality of the lens module, the optical element performs typically needs to undergo a variety of precision machining processes to obtain desired optical surface, shape, and surface microstructure. The optical elements are then assembled into the lens barrel according to a predetermined compact arrangement.
In fact, the lens module, particularly optical elements, are arranged and assembled on the basis of a general environment, for example, normal temperature and atmosphere. However, the outside environment in real life is variable, and thus varying operating environment of the camera module. For example, in a cold situation, the camera module is subject to a lower temperature environment. Due to thermal condensation effect, original compact arrangement and microstructure of the optical elements are destroyed to a certain extent, thus leading to engagement flaws. This results in a relatively lower imaging quality. At the same time, due to the lower temperature environment, a certain amount of vapor condenses into water droplets on surfaces of the optical elements. The water droplets have a destructive influence on the imaging quality.
Furthermore, the effective refractive index of the optical elements varies with the temperature thereof. Thus, in cold situations, the effective refractive index of the optical elements is lowered by the lower outside temperature. Accordingly, the optical imaging system of the camera module might deviate from predetermined design thereby producing undesirable difficulty for the user to take pictures.
What is needed, therefore, is a lens module assembly that has a relatively stable imaging effect conforming to variation of outside temperature environments.
What is needed, also, is an imaging system having the desired lens module assembly.